| Grade 4: Structures and Mechanisms: Pulleys and Gears |
Achievement
Level
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Overall Expectations
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1
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2
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3
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4
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| •demonstrate an understanding of the characteristics
of pulleys and gears; |
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| •design and make pulley systems and gear systems, and
investigate how motion is transferred from one system to another; |
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| •identify ways in which different systems function, and
identify appropriate criteria to be considered when designing and making
such systems. |
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Specific Expectations
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| Understanding Basic Concepts |
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| •describe, using their observations, the functions of
pulley systems and gear systems (e.g., they make changes in direction,
speed, and force possible); |
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| •describe, using their observations, how rotary motion
in one system (e.g., a system of pulleys of different sizes) is transferred
to rotary motion in another (e.g., a system of various gears) in the same
structure; |
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| •describe, using their observations, how gears operate
in one plane (e.g., spur gears, idle gears) and in two planes (e.g., crown,
bevel, or worm gears); |
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| •demonstrate an awareness of the concept of mechanical
advantage by using a variety of pulleys and gears. |
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| Developing Skills of Inquiry, Design, and Communication |
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| •formulate questions about and identify needs and problems
related to structures and mechanisms in their environment, and explore
possible answers and solutions (e.g., test the effort required by different
gear systems to lift the same load); |
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| •plan investigations for some of these answers and solutions,
identifying variables that need to be held constant to ensure a fair test
and identifying criteria for assessing solutions; |
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| •use appropriate vocabulary, including correct science
and technology terminology, to describe their investigations (e.g., use
terms such as block and tackle in describing pulley systems and gear train
in describing gear systems); |
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| •compile data gathered through investigation in order
to record and present results, using tally charts, tables, and labelled
graphs produced by hand or with a computer (e.g., create a table recording
how the action of a pulley system is altered by changing the tension of
the band connecting two pulleys); |
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| •communicate the procedures and results of investigations
for specific purposes and to specific audiences, using media works, written
notes and descriptions, drawings, charts, and oral presentations (e.g.,
draw a diagram of a proposed object and a diagram of the finished product); |
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| •design, make, and use a pulley system that performs
a specific task (e.g., a pulley system that closes a door or carries an
object from one place to another); |
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| •design and make a system of pulleys and/or gears for
a structure (e.g., a potter’s wheel) that moves in a prescribed and controlled
way (e.g., fast, straight) and performs a specific function; |
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| •manipulate pliable and rigid materials (e.g., modelling
clay, wood) as required by a specific design task. |
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| Relating Science and Technology to the World Outside
the School |
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| •demonstrate awareness that most mechanical systems are
fixed and dependent on structures (e.g., elevators); |
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| •compare in qualitative terms the performance of various
mechanical systems (e.g., a block-and-tackle system, a single-pulley system),
and describe how they are used; |
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| •identify and make modifications to their own pulley
and gear systems to improve the way they move a load (e.g., change the
size of pulleys or gears used; use gears that change direction through
a right angle); |
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| •evaluate, in general terms (e.g., as more or less effective),
the performance of a system that they have made and the performance of
another system designed to do the same task; |
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| •explain how various mechanisms on a bicycle function
(e.g., levers for braking; gears and chains for changing speed); |
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| •demonstrate awareness that finishing techniques can
adversely affect the performance of a mechanical system (e.g., problems
result if paint gets into a gear system); |
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| •identify the properties of materials (e.g., pliability,
rigidity) that are best suited for use in a structure that contains a mechanical
system; |
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| •describe the consequences of having a limited choice
of materials when making a device or a structure; |
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| •identify common devices and systems that incorporate
pulleys (e.g., clotheslines, flagpoles, cranes) and/or gears (e.g., bicycles,
hand drills, wind-up or grandfather clocks). |
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| Student Name: |
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